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Vapor "Barrier" ...

Hangers,

Spent the last hour reading Vapor Barrier (VB) threads as dp hammocks and quilts use VB technology. ( small, light, not expensive, and easy to dry if necessary using synthetic insulation)

FYI: I've read often, the Mt. Everest climbers' down sleeping bags easily double in weight with moisture and ice, even tho they attempt to sun dry them out, if possible. It seems to me, at some point, synthetic insulation would be better than down?

Below is what works of me with Vapor Barrier technology ...

Synthetic long underwear and socks (don't like the VB feel against my skin)

Sleeping in pertinent clothes for temperature (NO cotton)

dp hammock that is nearly water proof (vapor barrier and can be used as rain gear)

dp top and under synthetic quilts with VB technology that is "next" to one's body, the outer fabric is DWR. (Allows for smaller, lighter gear in low temperatures)

Science often seems counterintuitive, and as with any piece of gear, VBLs only work well within a defined set of conditions. Just as you wouldn't say a winter quilt doesn't work well b/c it doesn't give good results in summer, a VBL will only give good results when used correctly.

Great illustration, dejoha!

Well said used at altitude or in severe winter conditions it works well , i use them over here in winter in the French Pyrenees , and get good results , it is a very good light weight piece of kit to carry on multi day sleep outs to test and find for your self and when your body reacts to the changes everyone is different,

I have a set of the RBH VBL cloths and they work great, but not sure whether this has come up in the post but most "waterproof", "breathable" fabrics like your rain gear are neither and can be used as VBL without having to buy anything new.

So, as I understand this thread, I could use:
First layer: lightweight silk underwear top & bottom,
second layer:driducks raingear top & bottom,
third layer: fleece pajamas,
then on feet: silk socks, bread bags, wool socks or down booties,
hands get thinnest possible gloves, surgical gloves, mittens.

Yeti under WBBB & TQ over all. Then just "ignore" the clammy feeling???

Would the driducks work differently if put on "inside-out" ?

Real curious about this thread.

It is important to remember with VBL technology that you need to vent...
You can't just put it on, zip it up and leave it. The idea is the you create a microclimate close to your skin that lets you stay warm in cold temperatures ( traps body heat) but you have to pay attention to your temperature and not overheat which will cause you sweat and feel "clamy" the idea is then to reabsorb that moisture and not let it escape. Most people don't like the feel of the VBL right nex to their skin so they use a thin base layer, this if perfectly fine, but more attention needs to be paid to your "inner climate"
I hiked once in North Dakota in January at -23 degrees and was only wearing a base layer and a VPL jacket and still needed to have it unzipped half way about every 30 minutes.

This past weekend I was backpacking the San Francisco Peaks in northern Arizona. We set up our hammocks on the steepest incline I've ever hung on, not far from the trail, at 11,300 ft. It wasn't suppose to get very cold, maybe in the low 40s.

However, that night my body was pretty beat up with the days mileage and altitude and I was close to shivering in my 40°F-rated down top quilt. I was wearing every bit of clothing I had.

There was no chance of rain that night so I took my rain tarp (a GoLite Poncho Tarp) and wrapped it around my legs and lower torso before going to bed.

While not the ideal temperature conditions, the effect was immediate and welcome. I slept in this makeshift VBL all night and slept warm and comfortable. Since the VBL wasn't completely sealed, I had some moderate ventilation, but this "burrito" style really helped my body regulate its temperature until my metabolism kicked in.

In the morning, I pulled off my top quilt and my legs were still warm and cozy inside my tarp wrap. Pulling the tarp away, my legs immediately felt cool. It was amazing.

Typically, VBLs are recommended only in very cold and dry conditions. I wanted to share this experience because it gave me a sort of "last resort" method for staying warm in unusual circumstances.

While I was wrapped up enough to stay warm, there were enough "leaks" for venting that I didn't have any condensation issues. It was also very windy all night, which likely helped pull away a lot of moisture.

............While not the ideal temperature conditions, the effect was immediate and welcome. I slept in this makeshift VBL all night and slept warm and comfortable. Since the VBL wasn't completely sealed, I had some moderate ventilation, but this "burrito" style really helped my body regulate its temperature until my metabolism kicked in.

In the morning, I pulled off my top quilt and my legs were still warm and cozy inside my tarp wrap. Pulling the tarp away, my legs immediately felt cool. It was amazing.

Typically, VBLs are recommended only in very cold and dry conditions. I wanted to share this experience because it gave me a sort of "last resort" method for staying warm in unusual circumstances.

Raisins bump of this thread helped me realize I missed your excellent report from last July, Dejoha. It is great to see this example of a VB saving you at least from an uncomfortable night in conditions that most would consider miserable for a VB, only in the 40s! That is NOT traditional VB weather, yet it saved your bacon, so to speak!

And you illustrated another point: only in the 40s, and due to being debilitated from a rough day, with a no doubt high quality 40F TQ plus all your clothing, you were close to shivering! Which probably would have only got worse during the night. That makes a point none of us should miss! May I ask, what was your UQ?

I bet you had some major evaporative cooling(EC) going on, even if temps were not very cold. VB to the rescue! Stops EC instantly! I'm betting that even if you had some minor condensation or clamminess, you still would have been warm. Better clammy than cold. Even if you outright sweat, better your thin base layers are damp than freezing from EC, plus that vapor is condensing or sweat soaking into your down night after night. The sudden evaporation of that moisture is what you felt when you finally took the tarp off, EC!

I see that 21% have used VBs successfully, much more than I would have predicted. I see that 73% have either never looked into them or are skeptical that they work at all. And 5% have used them and their clothes/insulation got really wet, which I assume was a negative experience. One which I have never experienced. I have been an advocate of VBs sense the 80s, when I got my 1st pair of Patagonia VB socks. For me, VBs have only served to keep my insulation dry as a bone, if you don't count the thinnest possible layer closest to my skin.

Over the years I have used VBs in various forms- mainly socks, but also glove inserts and most frequently space blankets in HH Super Shelters and in the bottom of a PeaPod. I plan to keep on using them, plus a VB shirt I have from Stephenson's Warmlite, and I hope to get some VB pants from them. I know you are supposed to be able to use your WPB rain gear as a VB, but I have a hard time seeing how it could work to full effect. Sense if I sit around in a true VB I tend to feel clammy as the humidity level at my skin reaches 100%. I never feel that in any of my WPB rain gear, so at least some vapor must be getting through.

Thanks for that informative real life report!

Last edited by BillyBob58; 10-17-2012 at 22:33.

For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
Romans 8:18,21-22

GREAT Thread! Massive information about VB. Not really something I had thought about before.

So for the simple and inexpensive option, assuming that someone did not have wads of cash to spend on VB clothing! You could use a VB bag, like the SOL or other brands, survival bag, just put in inside your sleeping setup not outside.

I used one of these survival bevies on the West Coast Trail last spring to stop the wind on a windy night, it worker great and I was warm all night, BUT it was on the outside of my sleeping bag (Ground camping) and when I woke the next morning the survival blanket had water on the inside and the outer shell of my bag was damp. Luck would have it that the morning was warm and sunny so I just hung them up and they dried quickly.

So if I was to do this again, of needed extra warmth for a cold night, the survival bevies should go inside the sleeping bag or top quilt, correct?

The one from Western Mountains looks like it was/is made for that, anyone have any experience with those? Are they noise makers like the SOL ones?

GREAT Thread! Massive information about VB. Not really something I had thought about before.

So for the simple and inexpensive option, assuming that someone did not have wads of cash to spend on VB clothing! You could use a VB bag, like the SOL or other brands, survival bag, just put in inside your sleeping setup not outside.

I used one of these survival bevies on the West Coast Trail last spring to stop the wind on a windy night, it worker great and I was warm all night, BUT it was on the outside of my sleeping bag (Ground camping) and when I woke the next morning the survival blanket had water on the inside and the outer shell of my bag was damp. Luck would have it that the morning was warm and sunny so I just hung them up and they dried quickly.

So if I was to do this again, of needed extra warmth for a cold night, the survival bevies should go inside the sleeping bag or top quilt, correct?

The one from Western Mountains looks like it was/is made for that, anyone have any experience with those? Are they noise makers like the SOL ones?

Wolf

In general, the idea is to have a VB between you and all layers of insulation. Because, as you experienced, whatever is between you and a VB will tend to get wet. Most will sacrifice a very thin layer of fast drying long johns between skin and VB, even though it will get damp, just because a VB feels pretty unpleasant against bare skin. That first layer will get damp, but all layers of thick insulation will remain bone dry, even if you have another sil-nylon water proof layer around all of the insulation.

Or the Stephenson's Warmlite VB clothing has a fuzzy layer on it meant to go against skin. The VB socks cost $8 and shirt $25. You won't be wearing these out to dinner and a date, they look pretty crappy. But they sure work, and you don't need to bother with a thin layer.

For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
Romans 8:18,21-22